Environment-resistant module, micropackage and methods of manufacturing same

ABSTRACT

An environment-resistant module which provides both thermal and vibration isolation for a packaged micromachined or MEMS device is disclosed. A microplatform and a support structure for the microplatform provide the thermal and vibration isolation. The package is both hermetic and vacuum compatible and provides vertical feedthroughs for signal transfer. A micromachined or MEMS device transfer method is also disclosed that can handle a wide variety of individual micromachined or MEMS dies or wafers, in either a hybrid or integrated fashion. The module simultaneously provides both thermal and vibration isolation for the MEMS device using the microplatform and the support structure which may be fabricated from a thin glass wafer that is patterned to create crab-leg shaped suspension tethers or beams.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional applicationentitled “Generic Environment-Resistant Package For MEMS” filed Jun. 7,2007 and having U.S. Ser. No. 60/942,511.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under W31P4Q-04-1-R001,awarded by the Army Aviation and Missile Command. The government hascertain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an environment-resistant modules,micropackages and methods of manufacturing same.

2. Background Art

The following references are cited herein:

-   [1] K. Najafi, “Micropackaging Technologies for Integrated    Microsystems: Applications to MEMS and MOEMS,” Proceedings of SPIE,    vol. 4979, p. 1, 2003.-   [2] S. W. Yoon, S. Lee, N. C. Perkins, and K. Najafi, “Shock    Protection Using Soft Coating as Shock Stops,” in Solid-State    Sensors, Actuators, and Microsystems Workshop, Hilton Head Island,    S.C., 2006, pp. 396-399.-   [3] J. Mitchell, G. R. Lahiji, and K. Najafi, “Long-term    Reliability, Burn-in and Analysis of Outgassing in Au—Si Eutectic    Wafer-level Vacuum Packages,” in Tech. Dig. Solid-State Sensors,    Actuators, and Microsystems Workshop, Hilton Head Island, S.C., June    2006, pp. 376-379.-   [4] W. Welch III, J. Chae, S.-H. Lee, N. Yazdi, and K. Najafi,    “Transient Liquid Phase (TLP) Bonding for Microsystem Packaging    Applications,” Solid-State Sensors, Actuators and Microsystems,    2005. Digest of Technical Papers. TRANSDUCERS '05. The 13^(th)    International Conference, vol. 2, pp. 1350-1353, 2005.

SUMMARY OF THE INVENTION

An object of at least one embodiment of the present invention is toprovide an environment-resistant module, a micropackage and methods ofmanufacturing same.

In carrying out the above object and other objects of the presentinvention, an environment-resistant module including a packagedmicromachined or MEMS device is provided. The module includes amicromachined or MEMS device including at least one bonding site and apackage having an inner surface which forms a cavity and an outersurface which communicates with the environment. The module furtherincludes a microplatform or isolation platform located within thecavity. The microplatform includes at least one bonding site. The deviceis coupled to the microplatform at their respective bonding sites. Themodule still further includes a flexible, thermally isolating supportstructure to support the microplatform and the device within the cavity.The microplatform and support structure provide both thermal andvibration isolation of the device. The module further includes a path ofelectrically conductive material formed on the microplatform and on thesupport structure.

The package may include a substrate and a capsule connected to thesubstrate at a bonding area to at least partially form the cavity.

The package may completely encase the microplatform and the device toallow hermetic or vacuum encapsulation of the microplatform and thedevice.

The module may include at least one feedthrough through the package toelectrically connect the conductive material to the environment.

The at least one feedthrough may include a vertical or a horizontalfeedthrough.

The vertical feedthrough may extend through the substrate or thecapsule.

The support structure and the microplatform may be defined by a layer ofa wafer such as a glass wafer.

The substrate may include a wafer such as a semiconductor wafer.

The support structure may include a plurality of isolation suspensionbeams or tethers.

The module may further include a heater and a temperature sensor formedon the microplatform.

The module may still further include at least one shock absorption layerformed inside the package.

The module may further include at least one anti-radiation shield formedinside the package.

The module may still further include a getter layer formed inside thepackage.

At least a portion of the package may be optically transparent.

At least a portion of the package may be open to the environment.

Further in carrying out the above object and other objects of thepresent invention, a micropackage is provided. The micropackage includesa semiconductor wafer and an insulating layer or film bonded to thewafer. The insulating layer or film has a hole which extends completelytherethrough. Electrically conductive material is formed in the hole andis electrically connected to an isolated portion of the wafer. Theconductive material and the isolated portion of the wafer form asubstantially vertical feedthrough for signal transfer through thepackage.

The wafer may at least partially form a substrate or a capsule of thepackage.

Still further in carrying out the above object and other objects of thepresent invention, a method of making a module is provided. The methodincludes providing a micromachined or MEMS device including at least onebonding site. The method further includes providing a substrate andproviding a microplatform including at least one bonding site. Themethod still further includes providing a flexible support structure tosupport the microplatform above the substrate, aligning the respectivebonding sites and bonding the microplatform to the device at therespective bonding sites.

The support structure may be flexible and the step of bonding mayinclude flexing the support structure above the substrate. The substrateprevents flexing of the support structure beyond a predetermined amount.

At least one embodiment of a generic, wafer-level environment-resistantmicroinstruments (i.e., micromachined or MEMS devices) package andrelated processes are provided. This unique technique provides thermaland mechanical isolation from the environment, which may deteriorate thedevice performance. It also can package and handle a wide variety ofindividual MEMS chips or wafers in either a hybrid or integratedfashion, using a new and novel MEMS die transfer/assembly technique. Themicroinstrument is batch integrated/transferred onto a microplatform andsuspended over a substrate wafer by the thermal and mechanical isolationsuspensions. The microinstrument is then encapsulated in a cavity toprovide vacuum or hermetic sealing. Micro-heaters and temperaturesensors can be integrated to maintain the microinstruments at a fixedtemperature (oven-control). The electrical signal leads can be definedvertically or laterally.

Potential application areas using this technique are:

1. Low-power oven-controlled oscillator/resonator packaging.

2. High sensitive/performance inertial sensor packaging.

3. High performance pressure sensor or microphone packaging.

4. Optoelectric sensor packaging.

5. High performance IR sensor packaging.

The above object and other objects, features, and advantages of thepresent invention are readily apparent from the following detaileddescription of the best mode for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a and 1 b are schematic views of an environment-resistantmicroinstruments package constructed in accordance with at least oneembodiment of the present invention; FIG. 1 a is a side sectional viewwhile FIG. 1 b is a perspective view, partially broken away;

FIGS. 2 a-2 i are side schematic views, partially broken away,illustrating the environment-resistant microinstrument package processflow or method of at least one embodiment of the present invention;

FIG. 2 j is an exploded perspective view, partially broken away, of theresulting package;

FIGS. 3 a-3 d are SEM pictures or views of a via hole through glass witha contact metal layer; FIG. 3 a is a side view; FIG. 3 b is an enlargedview of a portion of FIG. 3 a; FIG. 3 d is a top view; and FIG. 3 c isan enlarged view of a portion of FIG. 3 a;

FIGS. 4 a-4 c are views or pictures of MEMS devices on isolationplatforms; the isolation platforms are fully suspended by the isolationsuspensions; FIG. 4 c is a picture or view of a transferred MEMS deviceon a platform supported by the suspensions;

FIG. 5 a is a picture of resulting packages; FIGS. 5 b-5 d are SEMpictures of vertical feedthroughs in the supporting substrate; thesilicon feedthrough is electrically isolated by silicon DRIE; FIG. 5 cis an enlarged picture of a portion of FIG. 5 b;

FIG. 6 a is a schematic perspective view, partially broken away, of apackage with a vertical feedthrough on the cap wafer; the cap part orcapsule may be made of a silicon-glass bonded wafer wherein a via ispatterned by a wet process; FIGS. 6 b and 6 c are pictures of siliconvertical feedthroughs which are electrically isolated by DRIE trenches;

FIG. 7 a is an exploded perspective view illustrating a portion of thetransfer process and FIGS. 7 b-7 f are side schematic views illustratingthe batch die-level transfer method;

FIGS. 8 a-8 h are side sectional views illustrating various aspects ofthe package with boxes in phantom; FIG. 8 a illustrates vacuum(hermetic) encapsulation; FIG. 8 b illustrates vertical feedthroughsthrough the substrate; FIG. 8 c illustrates the transfer method; FIG. 8d illustrates both thermal and vibration isolation; FIG. 8 e illustratesa second level vibration isolation; FIG. 8 f illustrates the packagewith an outlet; FIG. 8 g illustrates the package with a transparentwindow; FIG. 8 h illustrates the package which utilizes a SOG(silicon-on-glass) method;

FIGS. 9 a and 9 b are side sectional views of a package with anisolation platform made of silicon (Si) and isolation suspension made ofa thin dielectric film; FIG. 9 a shows the platform above the suspensionwhile FIG. 9 b shows the platform below the suspension; and

FIGS. 9 c and 9 d are side sectional views of a package with verticalfeedthroughs on the top wafer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Existing micromachined or MEMS device packages have not been able toprovide advanced isolation functionalities, for example, fromtemperature and vibration in efficient ways. Technical issues areaddressed herein for making advanced isolation possible as well asmaking the developed technology as generic as possible so it can beapplied to various applications without significant change.

A generic vacuum package that can suit a number of different devices andapplications, and that can provide isolation from environmentaldisturbances such as temperature and vibration will be of value for manyMEMS devices [1].

A new environmentally isolated package design, a generic transferapproach for the integration of monolithic and hybrid MEMS into thepackage, and new vertical feedthroughs for signal transfer are providedherein.

Package Design

FIGS. 1 a and 1 b are schematic views of one embodiment of the package.The package typically has three major components and in at least oneembodiment includes: (i) a supporting substrate such as a silicon waferthat may incorporate signal feedthroughs; (ii) a thin glass wafer whichprovides thermal and mechanical isolation using isolation suspensionsmade from the glass; and (iii) a cap silicon wafer or capsule for finalvacuum/hermetic encapsulation if needed. In this approach, the MEMS dieis flipped over and attached onto a glass microplatform, which is, inturn, supported by isolation suspensions over a shallow recess formed inthe supporting silicon wafer substrate. Interconnect lines are formed onthe glass suspension beams and transfer electrical signals between padson the glass microplatform and vertical feedthroughs through the bottomsilicon wafer. The attached MEMS die is oven-controlled by a heater andtemperature sensor integrated on the microplatform and is therebymaintained at a fixed temperature. Vibration isolation is provided bythe suspensions made of the glass.

The isolation suspensions should be stiff enough to mechanically supportthe platform and withstand shock/vibration, but long and flexible enoughto provide thermal and vibration isolation. Both of these requirementsare achieved using glass as the support and thermal isolation material.Glass has a relatively high Young's modulus and a low thermalconductivity. A thin (100 μm) glass wafer may be used to form thesesuspensions. The thin wafer is easy to etch and pattern using abatch-level wet etching process. Shock absorption layers [2], ananti-radiation shield for higher thermal isolation, and a getter layerfor the high vacuum environment may also be formed inside the package[3].

The MEMS device is fabricated on a separate substrate, and transferredonto a support substrate that is an integral part of a second wafer. Thetransferred device is vacuum or hermetically sealed on top by a capwafer. The electrical signal leads are defined vertically on the supportsubstrate. The vertical feedthroughs can be formed on the cap wafer orcapsule, and lateral feedthroughs are also possible.

The packages shown in FIGS. 1 a and 1 b can provide isolation from twodifferent sources: mechanical and thermal input. Mechanical isolation isprovided through two elements: isolation suspensions that damp out thelow-level and higher frequency vibration signals, and shock stops thatlimit the range of travel of the transferred device during high gshocks. Thermal isolation is also provided by these isolationsuspensions, which are designed and fabricated to have very high thermalresistance. A control method can be executed to keep temperatureconstant using a heater and a temperature sensor integrated on theisolation platform or on the MEMS dies. Since the devices are highlythermal-isolated, the power consumption for the constant temperaturecontrol is very low.

Glass tethers can be fabricated from a thin glass wafer, or from a thickglass wafer that is mechanically thinned, or from a thick depositedglass layer, or from a thick glass/oxide layer that is deposited on asemiconductor wafer using a number of different techniques.

Fabrication

FIG. 2 j is an exploded view of one embodiment of the package and FIGS.2 a-2 i illustrate a corresponding process flow. This process can bedivided into three major parts: (i) preparation of the supportingsubstrate, (ii) MEMS die transfer, (iii) final encapsulation andvertical feedthroughs formation.

Supporting Substrate Fabrication

Referring to FIG. 2 a, a shallow recess is formed in a standardthickness, highly-doped supporting silicon wafer using DRIE (DeepReactive Ion Etching), and a metal layer for shock absorption layer aswell as anti-radiation shield is deposited inside the recess. Gold istypically used because it is soft and highly reflective [2]. The siliconwafer is then anodically bonded to a 100 μm-thick glass wafer as shownin FIG. 2 b.

Referring to FIGS. 2 c and 2 d, via holes for the vertical feedthroughsare first wet etched into the glass wafer using a 49% HF solution, andthen filled with a metal film as further shown in FIGS. 3 a-3 d. The viaholes are filled by the metal layer. Good conformal coverage is shown.The measured contact resistance between the contact metal and the highlydoped silicon substrate shows ohmic characteristics with less than 2 ohmresistance. By this via and feedthrough structure, the footprint of thepackage can be reduced. A lateral feedthrough instead of the verticalfeedthrough can also be applied in this package.

Referring to FIG. 2 e, metal interconnection lines between the vias andthe bonding pads on the platform are then defined. Finally, theisolation platform and suspensions are patterned by wet etching theglass using a 49% HF solution as shown in FIG. 2 f.

In summary, first, a bottom recess is formed on the support bottomwafer, and the shock absorption and radiation shield layer is deposited.It is then bonded with another glass wafer, out of which isolationsuspension will be formed. For the vertical feedthrough interconnection,via holes are made by etching the glass wafer. The electricalinterconnection lines are defined and then the isolation suspensions arepatterned.

MEMS Transfer Process

Before transferring the MEMS dies, suitable metal layers are depositedon the MEMS die using a shadow mask process. The shadow mask may be madeof patterned SU8 film on a silicon wafer with several holes, each ofwhich corresponds to each of the bonding pads on the MEMS die.

Referring to FIG. 2 g, MEMS dies are then flipped over and bonded to thepads on the glass isolation platform using transient liquid phase (TLP)bonding [4]. The process sequence and results are shown in FIGS. 7 a-7f. The alignment of the MEMS dies to the substrate is done using amicromachined guide wafer of FIG. 7 a. It has through-wafer holes whereeach of MEMS dies is placed. This transfer/bonding process is a batchprocess and could support any size and shape die. The glass platform issupported using the flexible glass suspensions (FIG. 7 b). It isflexible enough so when the die is being bonded to the platform it bendsand touches down on the bottom silicon wafer (i.e., FIG. 7 e), but itsprings back up due to the high stiffness of the suspensions (i.e., FIG.7 f). The guide wafer is removed after die attach and bonding. Alltransfer/bonding process is done using standard wafer bonding equipmentincluding a standard wafer bonding tool (FIGS. 7 d and 7 e).

This transfer technique has several advantages. First, it is generic.Therefore, any kind of MEMS device can be assembled since the dies aretransferred after they are fabricated using any given process. Second,the electrical and mechanical connections between the isolation platformand the MEMS die are performed at the same time. Third, it providesflexibility to both the MEMS device and the bonding pad materialselection since the materials required for bonding are deposited afterthe MEMS device fabrication. In addition to various kinds of TLPbonding, other die attachment approaches, such as thermo compression andsolder bonding can also be used. A requirement may be that the dieattach bond should survive the temperature of the bonding step describedhereinbelow to achieve hermetic/vacuum encapsulation.

In summary, the technique is generic, so that any device with differentsize, shape and contacts location can be transferred at a time; aprecise alignment is possible during the transfer; the electricalconnection between the isolation platform and the substrate is possibleat the moment of the transfer bonding; and various bonding mechanismsuch as In—Au TLP, Au—Au thermal compression bonding can be used for theattachment of MEMS device to the platform.

FIGS. 4 a-4 b show the isolation platform and the transferred die isshown in FIG. 4 c which is a SEM image of the fabricated isolationsuspension with electrical interconnection. The thin metalinterconnections are patterned, and then the isolation suspension isdefined. The suspension design provides thermal/mechanical isolation andelectrical lead out.

Wafer-Level Encapsulation

Referring to FIG. 2 h, vacuum/hermetic encapsulation is achieved using acap or capsule bonded to the supporting substrate. This can be doneusing a variety of bonding techniques, including anodic and Au—Sieutectic bonding.

FIGS. 5 a-5 d shows the picture of the fabricated packages, and the SEMpictures of the vertical feedthrough, which is formed in the supportingsubstrate. The vertical feedthroughs are electrically isolated bysilicon DRIE. Either wire-bonding or a flip-chip technique can beapplied. The samples in FIG. 5 a are fabricated using anodic bonding.

Referring to FIG. 2 i, after vacuum packaging, the vertical feedthroughsare completed and formed by DRIE etching through the supporting siliconwafer from the backside. This vertical feedthrough technique reduces thefootprint of the package, and, unlike lateral feedthroughs, enables theuse of flip chip bonding of the die. The vertical feedthrough is veryrobust in that it shows no problem with wire bonding. The measuredcontact resistance is <2Ω (this is measured between the metal on theglass substrate to the bottom of the Si feedthrough, which is low enoughfor most applications).

Results

A thermal impedance of 3000K/W has been measured for the isolationplatform, which corresponds to a power consumption of 43 mW when theplatform is oven-controlled at 80° C. and the external environmenttemperature is −50° C. The thermal isolation can be modified andimproved as needed for different applications. The resonant frequency ofthe platform after a 4.5×4.5×0.5 mm³ MEMS die is transferred andattached to the platform has been calculated to be <1 kHz. This resonantfrequency can be designed to suit a particular application for vibrationisolation. The vacuum and hermeticity of the package is determined bythe bonding techniques. For example Au—Si eutectic bonding has beenshown to provide sub-10 mTorr vacuum with <2 mTorr variation for almosttwo years [3].

Conclusion

A new, robust, and generic way of packaging MEMS for isolation againstenvironmental parameters has been developed. Thermal and mechanicalisolations are achieved simultaneously using glass isolationsuspensions. The packaging technology allows for both wafer-level anddie-level packaging of MEMS devices, and can handle a wide variety ofMEMS chips. The package is capable of both hermetic and vacuumencapsulation, and provides vertical feedthroughs through the packagesubstrate to save space. This approach is suitable for many differentMEMS devices, including high performance gyroscopes, accelerometers,infrared imagers, or any applications requiring low power temperaturecontrol, vibration isolation, and hermetic/vacuum packaging for stableoperation.

Elements and Variants

The environment-resistant MEMS package can be broken down into keyelements. FIGS. 8 a-8 h show each element of the developed technologywith boxes in phantom lines. Also, FIGS. 8 a-8 h show otherpossibilities that can be derived from the technology that has beendeveloped.

FIG. 8 a shows vacuum/hermetic encapsulation by a silicon-insulator(glass)-silicon structure. The bonding method can be various such asanodic bonding, solder bonding, intermetallic bonding, etc.

FIG. 8 b shows vertical feedthroughs using vias through the insulatinglayer (glass) and silicon substrate isolation. Metal is filled in thevias for the electrical interconnection. The feedthroughs can be locatedin either the support substrate or the cap wafer.

FIG. 8 c shows the generic die-to-wafer transfer and assembly method.

FIG. 8 d shows thermal and vibration isolation by the isolationsuspensions.

FIG. 8 e shows 2^(nd)-level vibration isolation by suspensions formedout of a supporting wafer.

FIG. 8 f shows packaging (encapsulation) with an outlet forcommunicating between the packaged device and the environment. This maybe for pressure sensor and microphone applications.

FIG. 8 g shows packaging (encapsulation) with a transparent window.Image sensor and IR sensor are possible applications.

FIG. 8 h shows an integrated silicon-on-glass (SOG) process.

Any possible combination of above, for example, the encapsulation ofFIG. 8 f and the SOG of FIG. 8 h.

FIGS. 9 a and 9 b show potential modifications of the isolation platformand suspensions. Instead of using a glass wafer for both platform andsuspension material, it is possible to form the isolation platform outof a Si wafer and the isolation suspension out of a dielectric film(possibly thin glass wafer). As shown in the figures, the isolationsuspension can be located at the top or bottom of the isolationplatform.

FIGS. 9 c and 9 d and FIGS. 6 a-6 c show potential modification of thevertical feedthroughs. The vertical feedthroughs can be formed in thecap wafer or capsule. Dielectric film (possibly thin glass wafer) forelectrical isolation between vias can be located either at the top orbottom of the cap wafer as shown in FIGS. 9 c and 9 d, respectively. Thevertical feedthroughs can be fabricated in the cap wafer (top verticalfeedthrough) using the same technique used in forming the bottomvertical feedthroughs. FIG. 6 a is a schematic perspective view showingthe fabricated package with top vertical feedthroughs. In this case, viaholes are exposed on the outside of the package.

Although individual dies and transfers are shown, the technology willalso work with full wafers containing actual MEMS devices. A devicewafer would be bonded, for example, to the platform substrate and thenthe device wafer would be diced or etched to singulate the individualdies.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. An environment-resistant module including a packaged device, themodule comprising: a device; a package having an inner surface whichforms a cavity and an outer surface which communicates with theenvironment; a microplatform located within the cavity, the device beingsupported on the microplatform; and a flexible, thermally isolatingsupport structure to support the microplatform and the device within thecavity wherein the microplatform and support structure provide boththermal and vibration isolation of the device wherein both themicroplatform and the support structure are substantially planar in alateral direction and are at least partially defined by a single waferand wherein the package has a relatively low profile.
 2. The module asclaimed in claim 1, wherein the package includes a substrate and acapsule connected to the substrate at a bonding area to at leastpartially form the cavity.
 3. The module as claimed in claim 1, whereinthe package completely encases the microplatform and the device to allowhermetic or vacuum encapsulation of the microplatform and the device. 4.The module as claimed in claim 1, further comprising electricalinterconnections coupled to the device and at least one feedthroughthrough the package to electrically connect the device to theenvironment.
 5. The module as claimed in claim 4, wherein the at leastone feedthrough includes a vertical feedthrough.
 6. The module asclaimed in claim 4, wherein the at least one feedthrough includes ahorizontal feedthrough.
 7. The module as claimed in claim 5, wherein thevertical feedthrough extends through the substrate.
 8. The module asclaimed in claim 5, wherein the vertical feedthrough extends through thecapsule.
 9. The module as claimed in claim 1, wherein the supportstructure and the microplatform are defined by a layer of a wafer. 10.The module as claimed in claim 9, wherein the wafer is a glass wafer.11. The module as claimed in claim 2, wherein the substrate includes awafer.
 12. The module as claimed in claim 11, wherein the wafer is asemiconductor wafer.
 13. The module as claimed in claim 1, wherein thesupport structure includes a plurality of isolation suspension beams ortethers.
 14. The module as claimed in claim 1 further comprising aheater and a temperature sensor supported on the microplatform.
 15. Themodule as claimed in claim 1 further comprising at least one shockabsorption layer formed inside the package.
 16. The module as claimed inclaim 1 further comprising at least one anti-radiation shield formedinside the package.
 17. The module as claimed in claim 1 furthercomprising a getter layer formed inside the package.
 18. The module asclaimed in claim 1, wherein at least a portion of the package isoptically transparent.
 19. The module as claimed in claim 1, wherein atleast a portion of the package is open to the environment.
 20. Themodule as claimed in claim 1, wherein the support structure and themicroplatform are at least partially defined by a single layer.
 21. Themodule as claimed in claim 1, wherein the support structure is at leastpartially defined by a film.
 22. The module as claimed in claim 1,wherein the wafer is a glass wafer.
 23. The module as claimed in claim1, wherein the microplatform and the support structure are made of thesame material.
 24. The module as claimed in claim 1, wherein themicroplatform and the support structure are substantially coplanar. 25.The module as claimed in claim 1, wherein the wafer is a silicon wafer.26. The module as claimed in claim 1, wherein the device is anaccelerometer.
 27. The module as claimed in claim 1, wherein the deviceis a gyroscope.